Hi,
There is currently no implementation in the api to clone snapshots or
images. I wonder if we could add an XML node to specify a backed device.
Or add a new function that allows to clone.

I think this wants to be done with a new API, taking a source volume,
and destination pool as the arguemnts. Something along the lines of
virStorageVolClone(virStorageVolPtr src,
virStoragePoolPtr dst,
unsigned int flags);